Magnetron sputtered Si–B–C–N films with high oxidation resistance and thermal stability in air at temperatures above 1500 °C

Novel quaternary Si–B–C–N materials are becoming increasingly attractive because of their possible high-temperature and harsh-environment applications. In the present work, amorphous Si–B–C–N films were deposited on Si and SiC substrates by reactive dc magnetron cosputtering using a single C–Si–B or B4C–Si target in nitrogen-argon gas mixtures. A fixed 75% Si fraction in the target erosion areas, a rf induced negative substrate bias voltage of −100 V, a substrate temperature of 350 °C, and a total pressure of 0.5 Pa were used in the depositions. The corresponding discharge and deposition characteristics (such as the ion-to-film-forming particle flux ratio, ion energy per deposited atom, and deposition rate) are presented to understand complex relationships between process parameters and film characteristics. Films deposited under optimized conditions (B4C–Si target, 50% N2+50% Ar gas mixture), possessing a composition (in at. %) Si32–34B9–10C2–4N49–51 with a low (less than 5 at. %) total content of hydrog...